Dynamo or the like.



PATENTED SEPT. 10, 1907. G. A. VANDERVBLL 6: W. H. W. PROGTOR.

DYNAMO OR l'HI] LIKE. APPLICATION FILED 1.53.6, 1905.

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IzvdnZ'ars (krdzsufflzwwzz lflmas [6! Free for No. 865,782. PATENTEDSEPT. 10, 1907. G. A. VANDERVELL & W. H. W. PROGTOR.

DYNAMO 011 THE LIKE. APPLICATION FILED MAR. 6, 1905.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

CHARLES ANTHONY VANDERVELL, OF LONDON, AND WILLIAM HENRY,WARDEN PROCTOR,

OF COVENTRY, ENG-LAND.

DYNAMO OR THE LIIGE.

Specification of Letters Patent.

Patented Sept. 10, 1907.

To all whom it may concern:

Be it known that we, CHARLES ANTHONY VANDER- VELL and WILLIAM HENRYWARDEN PROCTOR, both subjects of the King of Great Britain and Ireland,and

residing at Willesden, London, England, and Coventry, in the county ofWarwick, England, respectively, have invented a new and usefulImprovement in or Relating to Dynamos or the Like, of which thefollowing is a specification.

This invention relates to improvements in dynamos or the like and hasfor its object to provide means whereby any desired constant output froma dynamo may be obtained in spite of the dynamo being driven at varyingspeeds.

According to this invention the dynamo is constructed so that when thedesired output is inclined to be exceeded the armature and the fieldmagnets are rotated in the same direction so that the relative speedbetween the two is maintained c nstant and the required outputmaintained in spite of fluctuations of speed.

A device of this kind is particularly advantageous in the case of adynamo driven by an internal combustion engine fitted to a motor car andused for charging batteries, lighting or the like and also for dynamosused on railway trainsior lighting purposes. In such cases the speed atwhich the rotating element such as the armature is rotated is constantlyvarying with the result that the output from the dynamo fluctuates andis liable to exceed the safety limit with disastrous results. Thedevices used to effect a constant output in the majority of casesconsist either of slip devices or shunt resistances or the like. Wherethese are employed, power is necessarily wasted when the speed andoutput exceed the normal.

In one construction of our invention we arrange in a suitable casing ashaft which is supported in bearings at each end, which shaft mayconstitute the driving shaft for the armature. pinion or the like,whereby it may be driven, a commutator and other devices which areusually fitted to the armature shaft of dynamos.

Arranged around the armature are the field magnets as usual. These fieldmagnets are not held stationary in the usual manner but are supported byarms connected to sleeves arranged around the armature shaft or otherconvenient part. The result of this method of carrying the field magnetsis that they are free to rotate concentric with the armature shaft." Theresistance to the rotation of the field magnets is adjusted according torequirements so that when the speed of the armature shaft exceeds whatis required to give the desired output the field magnets will be draggedround by the attraction of the rotating armature. In this This shaftcarries a sprocket.

way the relative speed between the armature and the field magnets isprevented from exceeding that which is necessary to give the desiredoutput.

Various methods may be employed for holding the field magnets stationaryand releasing them when re quired. For example, a brake may be arrangedto bear upon the field magnets, their casing or a brake drum or the likeconnected thereto. The brake can be adjusted by hand and can ifnecessary be adapted to be released by means of a centn'iugal or othergovernor when the, speed of the armature shaft exceeds be held in itsoperative position by a spring or the like and the pressure becontrolled by a suitable magnet or the like. This magnet is constructedso that when the speed ofthe armature shaft is above the normal it iscaused to reduce the pressure of the brake and allow the field magnetsto rotate and thus maintain constant speed in relation to the armature.In cases where the armature is held stationaryand the field magnets arerotated obviously a similar construction may be employed whereby thearmature is caused to rotate when the speed of the field magnets shaftexceeds the nor mal as describedv This invention consists essentiallytherefore in the construction-of a dynamo in which the armature and thefield magnets are both adapted to rotate, the one being driven from anysource of power, the other being held by a brake adjustable as to itsretarding effect upon the mechanism controlled by it the whole beingarranged in a suitable and compact manner whereby a constant output canbe obtained for varying speeds of theelement. I

In order that the invention may be the better understood it will now bedescribed in relation to the accompanying drawings, reference being hadto the letters and figures marked thereon.

Like letters refer to like parts of the various figures.

Figure l is a part sectional elevation of a machine constructed inaccordance with the present invention. Fig. 2 is an end elevation of thesame one of the field magnet coils being shown in section. Fig. 3 is adiagrammatic representation of the adjustable brake gear adapted with acentrifugal governor control. Fig. 4 is a similar brake gear adapted forelectromagnetic control and in connection therewith the mechanicalelements and the electric circuits are shown diagrammaticallyrepresenting the machine as shown in Fig. 1 but in this case thearmature is the driven element and the field magnets the braked elementas illustrating the obvious alternative arrangement hereinbeforereferred to.

Within a casing 11 and in ball bearings I; carried by said 0 ing, thefield magnets c are supported so as to the normal. In anotherconstruction the brake may,

revolve in the bearings b. These field magnets c are carried by aframework d which supports collecting rings e and commutator brushes f.Collecting brushes 9 are provided to rub upon the collecting rings a andconvey the current therefrom to the terminals h h. The shaft extension jof the field magnets which is external to the casing a carries a drivingpulley k or other equivalent device by which rotary motion can betransmitted to the dynamo. Within the casing d of the field magnets,ball bearings Z l are provided which support a shaft in carrying thearmature n and commutator 0. At the outer endof the shaft m a brakepulley p is fixedly carried, the periphery of which engages brake blocksq.

The brake clearly shown in side elevation in Fig. 2, is constructed insuch a way as to be practically supported in floating manner relative tothe shaft or rotating element being controlled by such braking mechanismand thus avoid differences of braking effect due to the rotating elementbeing out of true. This result is effected by supporting the brakeblocks on supports which will accommodate themselves to the movements ofthe brake drum. The brake blocks q are carried by lightflexible springsq by means of a block g pivoted to the extension 1* by means of the ping at one end while the other end is mounted on a block ,1 supported uponthe adjustable screwed spindle s engaging with the nut t in such a wayas to set up a pressure through the spiral spring it between the nut tand the block q. The nutt and the spring u are attached to one anotherwhile the spring n has one of its ends bent so as to engage in a hole inthe block q situated at that part where the spring it engages againstthe said block. The tension transmitted to the spring supports q isvaried by turning the spindle s by means of the handle 3 so as tocompress or extend the spring u according to the pressure it is desiredshould be put upon the blocks g. It will be noted that the blocks 9follow any eccentric movement of the drum p without making anyappreciable difference of the blocks upon the said drum. From thisconstruction it will be noticed the field magnets are adapted to rotateconcentrically with the armature shaft and that the resistance to therotation of the armature is adjusted according to requirements so thatwhen the speed of the field magnets exceeds what is required to give thedesired output the armature will be dragged round by the increasedattraction of the rotating field magnets and thus therelative speedbetween the field magnets and the armature is prevented from exceedingthat which is necessary to give the desired maximum output.

In the machine thus far described a simple hand adjustable brakearrangement has been provided but it is obvious modified methods may beemployed for holding the armature stationary and releasing it whenrequired for example in Fig. 3, a centrifugal governor o is showndiagrammatically which can be driven by the machine itself or by itssource of power by a driving band 11 and by means of toggle levers orother equivalent devices be adapted to release the pressure of the brakespringu in proportion to the increase in speed of the driving element orin Fig. 4 the same result may be effected electrically by means of asolenoid as acting on a magnetic core y; the solenoid being energized bythe current produced in the dynamo. When this current exceeds a givenamount the action of the solenoid overcomes some of the resistance ofthe spring a and the brake pressure is reduced. 1 It is obvious that thefield magnets may be controlled in a similar manner by the brake and thearmature be the driven element without in any way departing from theessence of this invention.

Having now described this invention, what we claim -and'desire to secureby Letters Patent is:

1. A dynamo consisting of a movable armature and movable field magnets,means for driving one of the said parts and u braking device for theother part adapted to be adjusted by hand while the machine is in motionso that the relative speed of rotation between the parts may be kept ata desired rate, said braking device comprising a pulley connected to thepart to be braked, a series of brake blocks adapted to engage with theperiphery of said pulley, a flexible spring carrying said blocks, astationary support for one end of said spring and an adjustable supportfor the other end of the spring. 5

2. A dynamo consisting of a movable armature and movable field magnets,means for driving the field magnets, a pulley connected to the armature.a series of brake blocks adapted to engage with said pulley, a flexiblespring carrying said blocks, a stationary support for one end of said 0spring, a block 11 connected to the other end of the spring, a screwspindle on which the block (1 is movably supported a stationary notsupporting the spindle and a coiled spring on the spindle between thenut and the block (1 5 In testimony whereof, we have signed our names tothis specification in the presence of two subscribing witnesses.

Witnesses i RICHARD A. HOFFMANN,

CHARLES CARTER.

